The invention relates to an apparatus which is adapted for depositing biological material in a substrate material, in particular to a deposition apparatus which is adapted for embedding biological cells or cell components in the substrate material. The invention also relates to methods for and applications of the deposition of biological material in a substrate material.
It is generally known in practice from biological or medical methods to transfer biological cells from a cell culture or donor organism to a substrate. On the substrate, the cells are subjected for example to a test or to further culturing. The substrate to which the cells are transferred may be part of a laboratory device, such as for example a culture vessel, or a biological material, such as for example a cell culture or a tissue in a biological organism. While numerous techniques (e.g. dispensing techniques, picking/spotting techniques, etc.) are available for depositing biological cells on solid substrate surfaces, the technique concerning the targeted and reproducible deposition of cells or cell components in biological material has been developed only to an insufficient extent.
In order to embed cells in the tissue of an organism for example for medical purposes, a suspension of the cells has until now been injected directly into the relevant tissue or into the bloodstream of the organism. The injection of cells into tissue, e.g. heart muscle tissue, has the disadvantage that, during the injection, the dense material of the tissue has to be displaced, with the suspended cells being subjected to high mechanical stress. Furthermore, it is disadvantageous that usually considerable volumes of liquid are introduced into the tissue during the injection, which are undesirable or cause injury to the tissue. Finally, the injection results in undefined depositions, since the distribution of the cells in the tissue can barely be influenced. Injecting the cells into the bloodstream does allow a gentle transfer into the organism; however, the problem of geometrically undefined deposition increases still further. In the bloodstream, a drifting of the cells into parts of the organism outside the target tissue may lead to undesired side effects, which may even go as far as tumor formation.
In the case of injecting stem cells or precursor cells into a cell culture or a biological organism, there are additional requirements which are met only insufficiently by conventional methods. Stem cells are extremely sensitive types of cell, the state and differentiation potential of which are influenced by mechanical and biochemical environmental conditions and particularly surface contacts. An effective therapy using stem cells, which are intended to differentiate into a specific cell type in the target tissue for example, requires a gentle transfer and a reproducible deposition in the target tissue. A locally reproducible deposition requires not only the deposition of the cells in the desired target tissue, but rather also the precise setting of the number, depth position and/or mutual spacings of the embedded cells in the target tissue.
WO 2004/074426 describes a method for the gentle transfer of biological cells into biological tissue using a transfer tool which causes displacement without causing injury. This technique may be disadvantageous in practice if large numbers of cells are to be transferred. By way of example, in regenerative medicine the task may be to introduce 106 to 108 cells and accordingly a suspension volume of a few milliliters into a tissue. Since the positioning of the transfer tool is extremely time-consuming, the technique described in WO 2004/074426 may be unsuitable for a routine deposition of such large numbers of cells.
EP 1637173 A2 discloses a needle-free method for introducing genetic material through skin into biological tissue. In particular, very small particles which do not damage the skin cells are to be introduced into the interior of cells. The particles are transported by a gas flow. DE 69732106 T2 also describes supplying small particles into the interior of living cells, wherein the particles are first arranged in a carrier cartridge and then are conveyed into the substrate by an air stream.
In principle, the use of frozen biological materials is known in practice from biological methods. WO 94/07603 discloses a method for cryofixing biological materials to a solid body by means of a compressed air device. Cells frozen in a cuvette are known for electroporation purposes from U.S. 2005/0214946 A1.
U.S. Pat. No. 5,219,746 A and U.S. Pat. No. 5,036,006 describe methods for transporting small particles into biological tissue by means of air pressure. Here, too, biological particles in frozen form are administered. Both methods are aimed towards transporting small particles with diameters in the range from 10 nm to a few micrometers into the interior of cells, without destroying the cells in the target substrate in the process. A transport or deposition of larger cells or of whole cell groups is thus not possible.
The abovementioned problems occur not only in the deposition of stem cells, but rather also during the introduction of other cell types, cell components or active substances when a gentle transfer without losses under predefinable geometric or quantitative conditions is necessary. By way of example, the targeted deposition of active substances, such as for example differentiation factors or growth factors, in tissue is a problem that has not yet been solved. Furthermore, said problems occur not only during the deposition of biological material in an organism, but rather also during the embedding of biological material in biological or non-biological substrate materials outside an organism, such as for example in a cell culture.
The objective of the invention is to provide an improved deposition apparatus which is adapted for depositing biological material in a target substrate and by means of which disadvantages of conventional deposition techniques are overcome. The objective of the invention is also to provide an improved method for depositing biological material in a target substrate, by means of which disadvantages of the conventional techniques are overcome.
These objectives are achieved by a deposition apparatus, an injector cartridge, a method for depositing biological material and also by a use of biological material and a use of an injector cartridge of the invention.